This project will examine the relation between mood, autonomic hyper-arousal, and alcohol use in real-time, and determine whether autonomic hyper-arousal responses to standard stimuli in the laboratory are related to affect-alcohol relations in daily life. Method Using ambulatory physiological and self-report assessments, participants with difficulties in emotion regulation (i.e., meet criteria for borderline personalit disorder) and community controls will provide information regarding mood and drinking over the course of a week. Autonomic hyper-reactivity will also be assessed in the laboratory, in order to provide a comparison for real-time data. Long-Term Objectives Results from this project will inform negative reinforcement models of alcohol use and help identify physiological endophenotypes for alcohol use disorders. Training Aims The fellowship applicant will learn about autonomic nervous system functioning, analysis of psychophysiological data, analysis of intensive longitudinal data, and will gain experience communicating findings from this study in appropriate scientific journals. This will prepare the applicant for a career using translational research to study physiological and affective risk factors for alcohol use.